Background: C-type natriuretic peptide production by the heart in patients with chronic heart failure has recently been demonstrated by measuring the difference in C-type natriuretic peptide plasma levels between the aortic root and coronary sinus samples. To assess this previous relevant observation, we re-evaluated the cardiac production of C-type natriuretic peptide, thus increasing the total number of patients studied. In light of the difficulty in recruiting patients with these characteristics, this kind of study can be performed with a small number of subjects.
Methods: Cardiac production of C-type natriuretic peptide was evaluated in a subset (n = 6) of patients, referred to our institute for the evaluation of chronic heart failure. C-type natriuretic peptide was measured in the coronary sinus and in aorta blood collected during right and left heart catheterization using a specific immunometric assay, after solid-phase extraction of plasma samples.
Results: Significantly higher C-type natriuretic peptide levels were found in the coronary sinus than in aorta blood (7.8 +/- 1.3 versus 6.1 +/- 1.5 pg/ml, P = 0.034) and our results were in accordance with previous ones. Analysing as a whole the data gathered in the two studies, a noteworthy significant increase was observed (n = 15, P = 0.002) between the C-type natriuretic peptide concentrations in the two sites.
Conclusions: The results of the present study strengthen the hypothesis that C-type natriuretic peptide is produced by the heart in patients with chronic heart failure.